This will be the first major conference on the structure, biology and pharmacology of abasic sites in DNA. The meeting will be attended by over one hundred scientists mainly, but not limited to, from the United States and France. Scientists will represent universities, research institutes, industries, and government agencies. A wide range of mutagenic, carcinogenic and antitumor agents which damage DNA have abasic and related sites as a common intermediate in repair. Progress in chemical and biophysical methods have significantly contributed to our understanding of the structure and reactivity of abasic sites. Molecular biological and biochemical methods have advanced our knowledge concerning the importance and fate of these sites. In addition to the fundamental scientific interest in abasic sites, the place of these sites in DNA repair pathways presents a potential drug target for cancer chemotherapy. This meeting will provide an occasion for researchers (chemists, biologists and pharmacologists) involved in the study of abasic sites to exchange ideas in a multidisciplinary atmosphere. There will be formal morning and evening presentations and poster sessions. Poster sessions will provide an opportunity for all present to present their most recent work in further detail. Formal sessions will cover the structure of abasic sites, the enzymology of repair of abasic sites, drugs that interact with abasic sites, and the relationship of abasic sites with mutagenesis and toxicology. There will be an organized round table discussion on how different fields interact in a multidisciplined approach. Such an international conference should lead to new contributions towards our understanding of abasic sites as an intermediate in toxicology and mutagenesis and its effects on birth defects, carcinogenesis and aging.